This investigation was carried out in the Institute for Aerospace Research (IAR) 2D High Reynolds Test Facility (Ref. 1 to Ref. 3 and Fig. 1) to study the buffet characteristics of a supercritical airfoil DGK No. I (Fig. 2). Steady unsteady surface pressure and normal force were measured at various angles of attack and Mach numbers. The statistical properties of the normal force and pressure were carried out by spectral analyses. Buffet onset boundaries were evaluated from the divergence of the fluctuating normal force while buffet intensities were determined from the normal force measurements. The attached and separated flow regions on the airfoil as well as the merging of a shock induced separation bubble with the trailing edge separation region were determined by skin friction measurements.